The conventional safety door, such as a fire door and an emergency door, consists of one or the other of these two types of systems based on the type of door controller, that is, the failsafe system and the non-failsafe system. As the safety door is usually used as a door access system for ordinary people, these two door controller systems both have their merits and demerits in usage depend on the user,                (1) Failsafe system: In the situation of electricity failure, no matter what the reason is, the braking device of the door controller should immediately release the brake and shut off the safety door. In the event of a fire without electricity failure, the braking device will be released by cutting off the power by such as the smoke detector, temperature sensor, or other fire alarm detector, or through a fusible links melted in high temperature due to the fire and cutting off the power with a mechanical means, so that the safety door will slide down due to its own weight to be shut off. If the reason of electricity failure is definitely due to the fire, the device can stop the fire or exhaust of the smoke immediately after the fire. So, the system is preferred due to higher safety of fire protection. However, if the electricity failure is not due to a fire, the system will cause some inconvenience, and influence the normal entry/exit function. This should be the major defect. For example, the U.S. Pat. No. 5,850,865 belongs to the failsafe system category. In an event of unexpected electricity failure, the brake of this previous invention will actively be released after a delayed period, so the winding door will be fallen and shut off by its own weight.        (2) Non-failsafe system: In the situation of electricity failure for any reason, the braking device will turn into in braked status, and will not shut off the safety door immediately. After the fire-confirmation from the device such as the smoke detector, temperature sensor or other fire detecting devices, a back-up power source, such as a capacitor or battery, will temporarily supply current to the braking device to temporarily keep the brake releasing, or with a fusible links meted in high temperature under the fire to activate the braking device to release the brake by a mechanical means, so the safety door will be fallen due to its own weight and shut off. This type of system provides the advantage of not shutting off the safety door immediately after the electricity failure, if the reason of electricity failure is not due to fire, it will not prevent the user from passing through the door.        
The conventional non-failsafe system, such as the baking device (91) of the door controller as shown in FIG. 1a and b (irrelevant components not shown), the braking device (91) uses a brake release bar (92) to activate the brake or release the brake. One end of the brake release bar (92) is yieldingly biased by a spring (94) to be constantly at brake state; and, the other end is extended outwardly. An electromagnet (93) is positioned in opposite to the spring (94), and it includes a sliding portion (93a) connected to the brake release bar (92). Normally, when the door controller is energized to operate; the electromagnet (93) is energized for magnetic excitation at the same time, which activates the brake release bar (92) through the sliding portion (93a) to release the brake. The brake will remain in the braked statue in de-energized condition. In the case of an unexpected electricity failure, and if this is due to a fire, by melting a fusible links (95) sensitive to the temperature by the high temperature due to the fire, the brake will be released by a push rod (95b) yieldingly biased by the spring (95a), and the safety door will be fallen due to its own weight and shut off. Those who are skilled in the art should understand that if the reason of electricity failure was indeed due to fire, and if the firing location is at a certain distance away from the fire detecting device or the fusible links, it could not shut off the safety door at the instant of fire. Thus, the insufficient safety for fire protection would be the main weakness of this system.